RQS hulk-gelato

here's what i suggest -- take the decision out of your hands. let the size of your light and garden area dictate how large you should grow it. this will be more efficient use of your equipment / electricity etc. so, when it is roughly 2/3rds the Length x Width of the space you intend to fill (roughly = 1/2 size before stretch), then flip to 12/12 schedule and it should fill in the rest well. If it's a super-stretcher, can always prune overcrowding, if necessary. familiarity and experience will help you in future. 3 week vege is probably going to be a 30-60g plant and maybe some oddballs will be smaller/larger. If you think 3months is worth an ounce or 2, go for it... otherwise, each week you add will initially add proportionally more weight. growth increases until some genetic+environmental limit. Let your equipment and size of area make the decision for you...